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[I_want_an_Omega]

Ok, I want to add a double socket the other side of a wall to where one is already located. Simples methinks.

On closer inspection the existing one turns out to be a spur .............

The easiest thing in the world would be to drill through the wall and add the new socket off the back of the existing - but would I be breaking any rules/regs by doing that?

I could make the spur fused, but only at the end where the new socket would be - by extending the cable through the wall to a fused spur box, and then feed the output from that to the new socket and also back through the wall to the existing one if that makes sense?

Comments welcome.

Thanks - Rob

[aaronjb]

IIRC from reading the regs a while back, a spur can only run a single 13A socket unless the entire spur (from the spur point) is fed from an FCU, and then you can run more than one socket.. the way I read it, that means your double socket is already 'outside' of the 17th Ed..

[I_want_an_Omega]

IIRC from reading the regs a while back, a spur can only run a single 13A socket unless the entire spur (from the spur point) is fed from an FCU, and then you can run more than one socket.. the way I read it, that means your double socket is already 'outside' of the 17th Ed..

Thought so, - but, the original spur was added 12 years ago prior to 17th Ed. So I guess as long as I don't change it it can remain as it? Looks like this might be a bit more complex than envisaged. 

[aaronjb]

Yeah, if you don't touch something then the worst that can happen is a note on any future survey stating 'May not meet current regulations', as I understand it anyway.

Martian can probably help, he's qualified in this kind of thing

[Kevin Wood]

My recollection is that you can feed one fixed appliance, one single socket, or one twin socket from an unfused spur. I'm not an electrician, etc...

There is also a restriction on the percentage of outlets on a ring that may be spurs rather than directly connected to the ring.

[Kevin Wood]

I could make the spur fused, but only at the end where the new socket would be - by extending the cable through the wall to a fused spur box, and then feed the output from that to the new socket and also back through the wall to the existing one if that makes sense?

I meant to add that yes, I believe the above would be acceptable. The spur is then only feeding one "fixed appliance" (which happens to include some sockets). Total load will obviously be limited to 13A, so if the sockets are each intended to feed a fan heater, it won't work.

[I_want_an_Omega]

I could make the spur fused, but only at the end where the new socket would be - by extending the cable through the wall to a fused spur box, and then feed the output from that to the new socket and also back through the wall to the existing one if that makes sense?

I meant to add that yes, I believe the above would be acceptable. The spur is then only feeding one "fixed appliance" (which happens to include some sockets). Total load will obviously be limited to 13A, so if the sockets are each intended to feed a fan heater, it won't work.

The new ones would have printers plugged in & the existing one only gets used for the odd mobile fone charger. However, due to where it's located then it would be a real eye-sore to mount a fused spur box there. By extending the cable through the wall it puts the spur box out of sight.

[Martian]

You can't "spur off a spur" unlesss all the spurs are fed from a suitable FCU.

The easiest way to legally & safely add extra sockets would be to replace the existing socket with a socket/FCU combo and then feed off that.

[Martian]

Just to clarify the above, when I said swap the existing socket for a socket/FCU combo I was referring to the socket that feeds the existing spur rather than the spur itself.

[Kevin Wood]

Just to clarify the above, when I said swap the existing socket for a socket/FCU combo I was referring to the socket that feeds the existing spur rather than the spur itself.

Ahh, yes, that's true. FCU would need to be where the spur meets the ring.

[allen25]

I spent over 20 years in the electricity supply industry and have seen several hundred installations in my time. Regulations change as we know and I've often found wiring to different editions within the same overall installation. I frequently found 'extended' circuits that do not meet reg's for one reason or another. The most important point for me is that an installation is safe; polarity, earthing and appropriate fusing, meeting current (preferably) or appropriate reg's for the time. It may be possible for you to 'fuse down' part of your installation at the consumer unit to ensure you do not overload the circuit with too much load (too many appliances) for the cable to carry. Ring main circuits are typically fused at 30 amps which is more current than one 2.5mm t&e supply cable (spur) is designed to carry. There is a part of my own installation (to a building extension, as inhereted by me) that should have been wired as an extension to one of the existing rings but had been wired as several spurs. The only practical solution to this particular issue, without major decorative disruption was to fuse down the whole circuit, in this case fitting a 16amp MCB to the distribution board (which is backed by a RCD of course for this type of circuit). It is extremely unlikely that the demands of my circuit will ever exceed 16 amp unless several heating appliances are connected at the same time. You may be able to do this for your circuit depending on the way your installation is wired and the load that that part of the installation is required to carry. You could otherwise (if practical) fit a fusing point at the point the spur is connected to the ring main effectively fusing down that part of the installation.